Large diameter earth boring drill



5. w. BAUR ET AL LARGE DIAMETER EARTH BORING DRILL Aug. 16, 1960 FiledSept. 6, 1 957 3 Sheets-Sheet 1 I 1-43 2 Z 0 1. j l

'33 I I I ATTORNEY Aug. 16, 1960 G. w. BAUR ETAL 2,949,281

LARGE DIAMETER EARTH BIORING DRILL Filed Sept. 6, 1957 s Sheets-Sheet 2Gearqe W 5011/ f/"wm' A. Mar/0x1 INVENTORS BY @KM A rrax ws y -A.16;196o, G.W.BA'UR Em 2,949,281

- LARGE DIAMETER EARTH BORING DRILL 5 Sheets-Sheet 3 Filed Sept. 6, 1957George W Boar f/W/f? A. Mar/0x7 INVENTORS BY @KM Unite ieorge W. Baur,Pasadena, and Erwin A. Morlan,

Houston, Tex., assignors to Hughes Tool Company, Houston, Tex., acorporation of Delaware Filed Sept. 6, 1957, Ser. No. 682,373

8 Claims. (Cl. 255-327) This invention relates generally to anearthboring drill of the rotating cutter type and more particularly to:1) novel form of drill for drilling relatively large diameter ores.

In the drilling of earth bores for wells, shafts, tunnels, adits, andthe like, it is desirable to have a drill having operatingcharacteristics which render it suitable for any of these purposes, adrill which can be readily repaired without complete replacement, andone which may readily be had to drill the diameter of bore required. Itis the primary object of the invention to provide a drill whichsatisfies these requirements.

Another object of the invention is to provide a drillcapable of drillinglarge diameter bores but of such construction that in one form of theinvention it may be readily modified to drill a preselected size ofhole.

A further object is to provide a drill which utilizes cone type cutterswhich may be readily replaced when worn.

Still another object is to provide a drill having cone type cutterswhich are so related that relatively few types of cutting structures onthe numerous cutters will effectively cut bottom from the axis to thewall of the bore being drilled.

It is also an object to provide an earth boring drill which may beenlarged or reduced in size and which is so constructed thatsubstantially identical cutter assemblies thereon may be readilyreplaced when worn.

A further object is to provide a drill having grouped rolling cutters inwhich each group cuts an annular path on bottom and the cutters in thegroup are so related as to most effectively remove earth formation fromthe annular path.

An object of the invention is to provide an earth boring drill havingstepped nether surfaces, series of cutter assemblies being secured tosaid surfaces to disintegrate the bottom of a hole being drilled.

Still another and more specific object is to provide, in a preferredembodiment of the invention, a drill having a central portion adapted toform an earth bore of relatively small diameter and an annular extensionreleasably secured to said central portion and having a .series ofcutters thereon said cutters and the cutters on States Patent ice mentsof the individual cutters being omitted for sake of clarity;

Fig. 2 is a bottom plan view. of the drill of Fig. 1;

Fig. 3 is an enlarged detail showing the manner of releasably securing acutter assembly upon the bit head;

Fig. 4 is a radial section through the drill with portions of thecutting structure moved into the plane of the paper to illustrate themanner of cutting the entire bottom of the hole being drilled;

Figs. 5A, 5B, and 50 show groups of rolling cutters moved into the planeof the paper to illustrate the manner in which relatively few types ofcutting structures, on the numerouscones of a large drill, are capableof effectively cutting the entire bottom of the hole being drilled. V Adrill embodying the invention is shown at 10 and comprises a manifold 12and the cutter head assembly 13 to which are attached individual cutterassemblies 14. The manifold 12 and assembly 13 are integrated into acomposite structure and comprise the bit head.

The bit head is secured in any suitable manner to a tubular drill pipe.26}, here shown as a flange connection 21. The cutter head assembly '13is attached to the lower end of the manifold 12 as by the flangeconnection 22. V

The cutter head assembly 13 comprises a stem 23 having a radiallyextending plate or, flange 24 integral therewith and forming the nucleusor body of the assembly. Underlying and successively smaller than plate24 are plates 25 and 26. Also, overlying and successively larger thanplate 24 are plates 27 and 28. Cutter assemblies 14 are secured to therespective plates 24 to 28 by means of socket head cap screws 30 whichare accessible through aligned openings 31 in the overlapping plates.The complemental openings in the plate to which a cutter assembly issecured are counterbored at 32 (Fig. 4) so that tightening of the capscrews 30 effectively secure the cutter assemblies to the bit head.

As best shown in Fig. 3 it is preferable that a plurality of cap screws,shown as three in number, be used for adequately securing a leg to itsassociated plate. The overlying plates are similarly secured together bycap screws 33 located substantially on the bolt circle 34 (Fig. 3) butintermediate the points at which successive cut ter assemblies aremounted. Two of these cap screws are shown in dotted outline by way of,illustration in Fig. l althou-gh it is to be understood that anysuitable fastening means and in desired numbers may be used for thispurpose. V V

Each cutter assembly 14 comprises a downwardly extending leg 35 havingan inwardly and downwardly exall of the legs 35 are of the. same. sizeand each termithe central portion being operable to disintegrate thebottom of a relatively large diameter being formed by the drill.

A further object is to provide a drill in which successively largeroverlapping extensions may be releasably secured to a head of relativelysmall diameter to form a drill capable of cutting a large diameterborehole.

. .The foregoing together with otherobjects and advantages oftheinvention will be morefully apparent from the following descriptionand the accompanying drawings which illustrate the inventionand inwhich:

, Fig. lis a side elevational view of a drill embodying one form of theinvention showing the drill in position in the bottom of a bore beingdrilled, the cutting elenates at its upper end in a horizontal surfacecomplementa-ry to the nether surface of the plate to which it issecured.

Inorder to remove cuttings from the .bottom of the hole being drilled,the manifold 12 is provided with a plurality of fluid ducts 40 whichextend downwardly and outwardly and are attached through connect0rs42 toducts 41 passing through openings in the plates of the cutter headassembly. Flushing fluid may be' pumped downwardly through pipe 20 andthe ducts 40 and 41 to flush cuttings from bottom and upwardly about thebit 10 and drill pipe 20 to the surface. Alternately .the flushing fluidmay enter the lower ends of the ducts and carry the cuttings with itwhereby the cuttings would be 3 discharged from within the drill pipe 20at the surface. The arrow 43 indicates the alternate directions of fluidflow.

It has been found desirable to construct a drill of the type describedthat will form a hole 30 inches diameter when plates. 27 and zs andtheir assd ciated cutters are not used. The addition of plate 27 and itscutters will enlarge the drill to a 40 inch diameter and furtheraddition of plate 28 and its cutters will enlarge the drill to a 50 inchdiameter. While specific dimensions have been given it is to beunderstood that they have been given only by way of illustration and arenot limitative of the invention. v I Obviously as the plate 28 isremoved a new manifold 12 will be used, such manifold having the desirednumber and location of ducts 40 to accommodate the cutter head ofreduced diameter. The same is true when plate 27 and its associatedcutters are removed. H I

I In order to drill with a given weight or to drill with equipment notcapable of applying extreme weight to eifect cutting action it isimportant that the cutters 36 be provided with such cutting elements aswill adequately cover the bottom of the hole being drilled and yet havea limited amount of metal on bottom at any instant. The structureenabling the use of cutters of relatively small diameter assists inmaintaining this condition. Also, it is desirable from the standpoint ofcutter replacement to have as few types of cutters as possible. Toaccomplish these ends the illustrated embodiment of the invention usesonly siX types of cutters which are identified by reference characters11 to 6 inclusive.

In the lower portion of Fig. 4 there is shown the manner in which thecutting elements or teeth of the various cutters cooperate to cut thebottom of the hole. From Fig. 2 it is seen that the cutters are grouped,each group serving to cut an annular track. The innermost track is cutby cone 1. Cones 2 and 3 cut the next adjacent track and series of cones4 and 5 are grouped to cut the next three outermost tracks with theexception that cone 6 is included in the outermost group to supplementcones 4 and 5 in that group. This grouping is clearly shown invertically aligned Figs. 5A, 5B, and 5C which show the completeicuttingstructures on the respective cones and thus clarify the manner in whichthe cutter teeth cover bottom as illustrated in Fig. 4.

Operation of the improved earth boring drill of the invention isbelieved apparent from the foregoing description. By way of furtheramplification of the mode of operation and description it is assumedthat the drill is attached to 'a drill stem 20 through which is applied-adequate power to rotate the drill and suflicient force is appliedaxially of the drill stem that effective cutting action is had.Obviously, drilling may proceed in horizontal, vertical, or inclineddirection depending upon whether a w'ellfshaft tunnel or adit is beingformed.

During the drilling operation flushing fluid is supplied ito the drillto remove cuttings from the operating area.

For this purpose the flushing fluid may be supplied through the drillstem 20 or reverse flow may be had )bypuinping fluid downwardly aboutthe drill stem and thence through the ducts 40, 41 and the drill stem 20to .the surface. This latter manner of functioning may also be eifectedby application of suction to the interior of the drill stem 20.

Broadly the invention comprehends an earth boring grilll of the rollingcutter type for drilling large diameter I 0 es.

presenting stepped, downwardly facing, annular surfaces,

cutter assemblies secured to said surfaces and extending V downwardlytherefrom, each of said cutter assemblies ineluding a rolling cutterhaving radially extending cutting eleineh'ts tlier'oii, said headincluding a stem "extending axially thereof, therefbeing at least onepassage from the interior of said stem to the nether side of the headfor conducting flushing fluid to remove cuttings from the bottom of thehole being formed by the drill.

2. In an earth boring drill, a head comprising a plurality ofoverlapping annular plates secured together and presenting stepped,downwardly facing, annular surfaces, cutter assemblies secured to saidsurfaces and extending downwardly therefrom, each of said cutterassemblies including a rolling cutter having radially extending cuttingelements thereon, said head including a stem extending axially thereof,a plurality of conduits secured to said stern and extending outwardlyand downwardly through said head providing flushing fluid passagewaysfrom the interior of the stem to the nether side of the head.

3. In an earth boring drill, a head comprising a plurality ofoverlapping annular plates presenting stepped nether surfaces, cutterassemblies secured to said surfaces and extending downwardlytherefrom,each of said cutter assemblies ineludihg a rolling cutterhaving radially extending cutting elements thereon, said head includinga stern integral with and extending axially thereof.

4. In an earth boring drill a head comprising an annular body havingsuccessive outwardly extending annular nether surfaces, cutterassemblies mounted on said surfaces and extending downwardly therefromto'cutannular paths on the bottom and about the axis of a hole beingdrilled, each of said cutter assemblies including a rolling cutterhaving radially extending cutter elements thereon, and means forsecuring said head to a drill stem for effecting rotation of the drill.

5. In an earth boring drill, a head comprising an annular body havingannular nether surfaces extending successively upwardly and outwardlyfrom the axis of the body, cutter assemblies mounted on said annularsurfaces and extending downwardly therefrom to cut concentric paths onthe bottom of the hole being drilled, each of said cutter assembliesincluding a rolling cutter having radially extending cutter elementsthereon, and means for securing said head toa drill stem for effectiverotation of the drill.

6. In an earth boring drill, a head comprising a central body portionand at least one annular extension secured thereto and extendingoutwardly therefrom, the nether surface of said head presenting steppedannular faces, and cutter assemblies secured to said faces and extendingdownwardly therefrom, each of said cutter assemblies including a rollingcutter having radially extending cutting elements thereon, the cuttersof said as- References Cited'in the'file of this patent I UNITED STATESPATENTS 839,837 Guttzeit Jan. 1, 1907 2,090,356 Reed Aug. 17, 19372,149,798 Starkey Mar. 7, 1939 FOREIGN PATENTS 687,791 France May 5,1930

